Adapter pattern

Adapter.swift

import Foundation

// Adapter design pattern

protocol Payment {
    func recievePayment(_ payment: Double)
    var totalPayment: Double { get }
}

class NetBanking: Payment {
    private var total = 0.0
    
    func recievePayment(_ payment: Double) {
        total += payment
    }
    
    var totalPayment: Double {
        return total
    }
}

class UPI: Payment {
    private var total = 0.0
    
    func recievePayment(_ payment: Double) {
        total += payment
    }
    
    var totalPayment: Double {
        return total
    }
}

let upiPayment = UPI()
upiPayment.recievePayment(1000)
upiPayment.recievePayment(2000)
upiPayment.recievePayment(3000)


let netbankingPayment = NetBanking()
netbankingPayment.recievePayment(1000)
netbankingPayment.recievePayment(2000)
netbankingPayment.recievePayment(3000)

let payments: [Payment] = [upiPayment, netbankingPayment]

var total = 0.0
for payment in payments {
    total += payment.totalPayment
}

print(total)

// Third party class which doesn't support Payment protocol
class AmazonPayment {
    var payment = 0.0
    
    func paid(_ amount: Double) {
        payment += amount
    }
    
    func paymentSuccessful() -> Double {
        return payment
    }
}


let amazonPayment = AmazonPayment()

// This line will give error because AmazonPayment class don't support payment protocol

//let thirdPartypayments: [Payment] = [upiPayment, netbankingPayment, amazonPayment]

// Adapter class - Solution

class AmazonPaymentAdapter: Payment {
    private var total = 0.0
    
    func recievePayment(_ payment: Double) {
        total += payment
    }
    
    var totalPayment: Double {
        return total
    }
}

let amazonPaymentAdapter = AmazonPaymentAdapter()
amazonPaymentAdapter.recievePayment(100)

let thirdPartypayments: [Payment] = [upiPayment, netbankingPayment, amazonPaymentAdapter]

var totalThirdParty = 0.0

for payment in thirdPartypayments {
    totalThirdParty += payment.totalPayment
}

print(totalThirdParty)